Cooler or evaporator



SeP 4, 194,5 J. R. zwIcKl. 2,384,413

` COOLER 0R EVAPORATOR Filed Nov. 18, 1943 3 Sheets-Sheet. l

INVENTOR ATTORNEY Sept. 4, 1945. J. R. zwlcKL.

COOLER' OR EVAPORATOR Filed Nov. 18, 1943 3 Sheets-Sheet 2 OO0OO\ WOOOOO Il,

B\oooo'o'oo ooooooooo oooooo oooo 9000 ooo 0 OOO 000 0 0 000 OO 0 R. .Z WMU INVENTOR ATTORNEY Patented Sept. 4, 1945 UNITED s'rmlszs` PATENT orsl'csf COOLER R EVAPORATOR Joseph R. Zwiekl, East Orange, N. J., assignor to Worthington Pump and Machinery Corporation, Harrison, N. J., a corporation of Delaware Application November 18, 1943, Serial No. 510,745

Claims.

This invention relates to heat exchange apparatus, and more particularly to coolers or evaporators of the ltype employed in refrigeration systems `of thev closed circuit compression type employing a volatil refrigerant as a coolant.

An object of the present invention is to provide a cooler or evaporator which is constructed and arranged whereby a lower static head in the liquid coolant or refrigerating medium is provided relative to the static head existing in coolers or evaporators of the same size of approved types now in use. 'I'he providing of a lower static head in the llquidjrefrigerant in the evaporator results in a lesser'average temperature rise of the refrigerant abovelthat which corresponds to the suction pressure of the compressor in the system, which in turn results ina lower evaporation temperature of the liquid refrigerant surrounding the tubes;

or if the temperature of the liquid refrigerant t surrounding thevtubes is to be at a xedrdegree, then Vthe system is permitted to operaie at a higher vapor pressure, resulting in less work to be performed to provide the desired cooling of the id to' b'e' cooled.

Another object of the present invention is to provide an evaporator of the surface type wherein the coolant' surrounds a plurality of tubes through which the fluid to be cooled flows and in which the vaporlzing surface; i. e., the tube surfaces which are contacted by the coolant, is divided into a plurality of banks or nests, providing at least two liquid surfaces instead of the usual one liquid surface, thus resulting in a reduction of approximately one half or more in the exit velocity of the vapor' out of the liquid surface. This reduction of the exit velocity of the vapor out of the liquid surface results in reduction of the quantity of liquid refrigerant carried along, as spray, with the vaporized refrigerant, thus providing an evaporator or cooler which will tolerate a higher heat load per square foot of tube surface than those of approved construction which have only one liquid surface forvapor emission.

Another object of the present invention is to provide an evaporator or cooler as specified which is relatively simple in construction and of assembly, resulting in an evaporator whlch.'due to the reduced labor of assembly, may be produced at a lower cost than conventional types of evaporators.

A further object of the invention is to provide simple, relatively inexpensive means for filtering out any liquid refrigerant from the vapor during the passage of the vapor to the suction inlet of the compressor of the system in which the evaporator is employed.

A still further object of the present inventionv is to provide an evaporator structure in which rupture of parts. leakage, etc. as the result of expansion in the unit is eliminated. The evaporator of the present application comprises a circular cylindrical shell having the internal structural elements attached to the shell only at its ends, thus allowing bulging of the shell in the middle due to expansion when under pressure without disrupting any supporting or sealing joints in the structure. v

With these and other objects in view, as may appear yfrom the accompanying specification, the invention consists of various features of construction and combination oi. parts, which willbe first described in connection with the accompanying drawings, showing a cooler or evaporator of *a preferred form embodying the invention, and the features forming the invention will be speci'iically pointed out in the claims.

In the drawings:

Figure 1 is a longitudinal vertical section through the improved evaporator.

Figure 2 is a vertical cross-'section taken on the line 2-2 of Figure l.

Figure 3 is a vertical cross-section taken on the line 3-3 of Figure 1.

Figure 4 is a fragmentary perspective view of a part of the cooler structure.

Referring more particularly to the drawings, the improved cooler or evaporator comprises s. cylindrical shell I which, in its construction, is preferably rolled and welded from sheet metal having annular flanges 2 on its ends to which theA liquid headers 3 and 4 are attached in the usual manner. The fluid to be cooled enters the liquid header 3 through the inlet 5 and passes through the tubes 6 in the coolant, finally leaving the cooler through the outlet l. The number of passes through which the fluid to be cooled travels v in vthe cooler may be determined or provided as desired through the medium of partitions such as indicated at 8' in the fluid header 3 and 4.

The tubes 5 are arranged in banks or nests as clearly shown in Figures 2 and 3 of the drawings, and the tubes in the uppermost bank l are confined in a trough s formed of sheet metal and extending substantially throughout the length of the shell.

The coolant or refrigerant which contacts the outer surface of the tubes i and serves to` cool the fluid flowing through the tubes enters the cooler through the inlet l0 and is collected in the inlet collection box or chamber I I from where its flow is controlled by the float i2 which opens ized refrigerant nofws into the outlet chamber I the valve- I8. The liquid refrigerant then flows through the delivery header Il through a` plurality of longltudinally'spaced openings ilinto the trough l and over the tubes lin the upper tube nest I. The openings I5 arefpreferably arranged so that they will deliver the. incoming refrigerant towards the header plate lilat the adiacentendof theshell I. The liquid refrigerani.. not vaporized by the upper tube. bank I, overflows from the trough l through overflow passages Il which are spaced at'any desired positlon or positions along the length of the trough at itssides; the inner inlet ends ofthe overiiow Il are arranged so that all of the tubes l in the tube bank s will be submerged before any of the liquid refrigerant overilowsfrom the trough.

The refrigerant vapor produced by the heat transfer action of the liquid refrigerant contacting the tubes l in thenestorbank l passes upwardly into the vapor-collection space Il. in the shell directly above the tube nest l. and fromy this collection space it passes through the distributlon plate Il into the vapor outlet chamber- !l. The vapor-ized refrigerant passes from the vapor outlet chamber 2l through the outlet Il to theoompressor (not shown) of the refrigerating system. As clearly shown in Figures 2 and 3 of the drawings. the distribution platey il, which extendsat an angle longitudinally ofthe interior of the `shell I. isy provided with a plurality of properly spaced slots 22'to provide a substantially even distribution'of thevaporized refrigerant during its passage into the outlet chamber 2l.- A

A nlter 28 which is constructed of any suitable material such as relatively ne metal shavings is placed at a suitable distance under the` distribution plate Il and serves uralter out any liquid refrigerant which may be carried, in vspray form, with the vaporiaed refrigerant for the purpose of providing a relatively dry .vapor passing to the compressor.

'me liquid refrain-nuit over-sowing from the and` escape space 24 directly beneath the trough I and above the'tuhes4 l in the lower tube nests 2s and n. 'nu tube nem :s um n erm-- ther arranged so. as to provide escape lanes Il for the v aporiaed refrigerant, allowing the vaporiiied refrigerant to new fromthe various portions of the tubenests upwardly into the escape space-24 and from theneethrough the passages Il, formed along-each side of the trough {between-the trough and theinnerwsllof theshell I. into the vapor collection space It from which the vaporasabove described. 'l'hsprovisionoftheu'oug l and thearrangement of the tube nests 2l andv il provides plurality of liquid surfaces, that is,

atleasttwo,onebeingatthetopoftheliquidin the trough l, and the other atthe top of the liquid inthe space below the trough i, and by providing this plurality of liquid surfaces the exit velocity of the vapor is reduced approximately one-half which, of course, very materially reduces the quantity of liquid refrigerant carried Alsobytheprovisionofthetwodistinctliquld compartments and liquid levels'for the liquid refrigerant in the cooler, a lower static head in the` coolant or refrigerating medium is provided than would be provided if only a single liquid surface or single depth of the liquid refrigerant were maintainedin thev cooler. Thereduction of the static head results in a lesser average temperature. rise of the refrigerant above that which corresponds to the suction prsure of the compressor (not shown) in the system which in mrn resuits in an average lower temperature of the liquid refrigerant surrounding the tubes. or in the event the temperature ofthe liquid surrounding the tubesV is to be maintained at a given degree, then the provision ofthe lower static head in the refrigerant permits the system to operate at a higher vapor pressure resulting in a power savings to provide the desired degree of cooling.

The cooler or evaporator of the present invention is particularly designed and constructed to the endof simplifying and consequently reducing the cost of its assembly, and the structure is so arranged that after the'shell I has been formed. the entire. internal structure comprising tnetroughlthetubesupportplatesltandthex various other elements may be all assembledv and welded together after which the entire structure in its assembled form as one unit is moved longitudinally into the shell and then the variom parts are welded'at their ends to the inside of the shell. After this, the heads Il and Il' are fastened to the shell and' then the boti om plate of the trough l is welded to the head lates Il and Il'. This latter welding Operation i: facilitatedby the provision of openings" winch arev leftintheshell I topermit accesstothe interior thereof for the welding operation.` After theassembled internal mechanism has been welded into place. cover plates s2 are placed over the openings II and weldedinplaceto seal theshell. Aawill be noted by particular reference to Figure 4 of` the drawings. the trough structure. l comm-bes the bttoln plate Iltowhihthelltlelllttare` welded. The side plates terminateshort of the ends of the bottom plate Il and have their ends out-turned as shown at sl to properly space the side walls N of the trough from the interior of the shell I and also to provide means for welding or securely attaching the side plates Il to the shell. The plate ll, the side walls. Il as well as the structure which goes to makeup the outlet chamber Il are welded tothe shell only at their ends; thus'being free from rigid connectiarto the shell intermediate therein. they allow theV shell tobulgeatltscenterundereapanaionaction. lvzitkhllout disrupting any of the Jointaor caulng nwmbeimaenmihntasmvmtmisncc allowed to flow to the other sets of tubes.

along, as spray, with the vaporized refrigerant. 7g 2. Inan evaporator, a ahelLa pluralitydtiss extending through said shell, means for delivering a coolant into said shell for submerging said tubes, said tubes arranged in a plurality of sets. means whereby a vaporization surface of the coolant and vapor escape space will be provided above each set of tubes, means whereby a predetermined level of liquid coolant will be maintained in one set of tubes before liquid coolant is allowed to now to the other sets of tubes, said shell having a vapor outlet chamber therein to receive vaporized coolant from said vapor escape spaces, and

f a lter over the inlets to said chamber.

3. In an evaporator, a shell, a. plurality of tubes extending through said shell, means for delivering a coolant into said shell for submerging said tubes, said tubes arranged in a plurality of sets, means whereby a. vaporization surface of the coolant and vapor escape space will be provided above each set of tubes, means whereby a predetermined level of liquid coolant will be maintained in one set of tubes before-liquid coolant is allowed to flow to the other sets of tubes, said shell having a vapor outlet chamber therein to receive vaporized coolant from said vapor escape spaces, a

' illter over the inlets to said chamber, and said filter comprising closely packed metal shavings.

4. In an evaporator, a shell, a. plurality of tubes extending through said shell, said tubes arranged in superimposed sets with a vapor collection space, above the uppermost set, a trough-like structure enclosing the uppermost set of tubes, means for delivering a liquid coolant into said trough-like structure, said trough-like structure having overiiow openings arranged so that the uppermost tubes in the upper set will be submerged in liquid coolant before any liquid will overflow into the shell below the trough-like structure.

5. In an evaporator, a shell, a plurality of tubes extending through said shell, said tubes arranged in superimposed sets with a vapor collection space above the uppermost set, a trough-like structure enclosing the uppermost set of tubes, means for delivering a liquid coolant into said trough-like structure, said trough-like structure having overilow openings arranged so that the uppermost tubes in the upper set will be submerged in liquid coolant before any liquid will overflow into the shell below the trough-like structure, the tubes in the sets below the trough-like structure being arranged to provide a vaporization surface of the coolant and a vapor escape space above the tubes of each set.

6. In an evaporator, a shell. a plurality of tubes extending through saidshell, said tubes arranged in superimposed seis with a vapor collection space above the uppermost set, a trough-like structure `enclosing the uppermost set of tubes, means for delivering a liquid coolant into said trough-like structure, said trough-like structure having overflow openings arranged so that the uppermost tubes in the upper set will be submerged in liquid coolant before any liquid will overow into the shell below the trough-like structure, the tubes in the sets below the trough-like structure being arranged to provide a vaporization surface of the coolant and a vapor escape space above the tubes of each set, the sides of said trough-like structure intermediate its ends being spaced from the inner surface of the shell to provide vapor escape lanes chamber therein above said vapor collection from said vapor escape space to said vapor collection space.

7. In an evaporator, a shell, a plurality of tubes extending through said shell, said tubes arranged in superimposed sets with a vapor collection space above the uppermost set, a trough-like structure enclosing the uppermost set of tubes, means for delivering a liquid coolant into said trough-like structure, said trough-like structure having overiiow openings arranged so that the uppermost tubes in the upper set will be submerged in liquid coolant'before any liquid will overflow into the shell below the trough-like structure, the tubes in the sets below the trough-like structure being arranged to provide a vaporization surface of the coolant and a vapor escape space above the tubes oi each set, the sides of said trough-like structure intermediate its ends being spaced from the inner surface of the shell to provide vapor escape lanes from said vapor escape space to said vapor collection space, said shell having a vapor outlet space, and means to causesubstantially an equal distribution of vapor over said outlet chamber.

8. In an evaporator, a shell, a plurality of tubes extending through said shell, said tubes arranged in superimposed sets with a vapor collection space above the uppermost set, a trough-like structure enclosing the uppermost set of tubes, means for or' each set, the sides of 'said trough-like structure intermediate its ends being spaced from the inner surface of the shell to provide vapor escape lanes from said vapor escape space to said vapor collection space, said shell having a vapor outlet chamber therein above said vapor collection space, and a filter over the inlets to said outlet chamber.

u. In an evaporator, a cylindrical shell, end plates for the shell, heat transfer inducing means in said shell and comprising support plates and structures for controlling the fiow of liquid coolant in the shell, said plates and structures being formed in a unit and welded to said end plates and to the shell near its ends but being free from connection with the shell intermediate the endl; oi'

the shell, and tubes carried by said support plates whereby the heat transfer means may be assembled and inserted as a unit longitudinally into the shell.

10. In an evaporator, a shell, a plurality of tubes extending through said shell, said tubes arranged in a plurality of sets with at least one set of tubes disposed above the other sets, means for delivering a coolant into said shell and on to the tubes in said uppermost set, and means for retaining a suicient quantity of liquid coolant about the tubes in the upper set to maintain submergence thereof before the liquid coolant is delivered to the lower sets of tubes.

JosEPH R. zwicm... 

